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1.
Structure of CdTe(111)B grown by MBE on misoriented Si(001) 总被引:3,自引:0,他引:3
Single domain CdTe(111)B has been grown on Si(001) substrates tilted 1o 2o, and 4o toward [110]. All the layers started with a double-domain structure, then a transition from a double- to a single-domain
was observed by reflection high energy electron diffraction. A microscopic picture of this transition is presented. We also
measured the tilt between CdTe(111)B and Si(001). The result does not follow the tilt predicted by the currently existing
model. A new model of the microscopic mechanism of CdTe(111)B growth is presented. New evidence indicates that optimizing
the tilt of the substrate surface is very crucial in improving the CdTe(111)B crystal quality. 相似文献
2.
K. Maruyama H. Nishino T. Okamoto S. Murakami T. Saito Y. Nishijima M. Uchikoshi M. Nagashima H. Wada 《Journal of Electronic Materials》1996,25(8):1353-1357
(lll)B CdTe layers free of antiphase domains and twins were directly grown on (100) Si 4°-misoriented toward<011> substrates,
using a metalorganic tellurium (Te) adsorption and annealing technique. Direct growth of (lll)B CdTe on (100) Si has three
major problems: the etching of Si by Te, antiphase domains, and twinning. Te adsorption at low temperature avoids the etching
effect and annealing at a high temperature grows single domain CdTe layers. Te atoms on the Si surface are arranged in two
stable positions, depending on annealing temperatures. We evaluated the characteristics of (lll)B CdTe and (lll)B HgCdTe layers.
The full width at half maximum (FWHM) of the x-ray double crystal rocking curve (DCRC) showed 146 arc sec at the 8 |im thick
CdTe layers. In Hg1−xCdxJe (x = 0.22 to 0.24) layers, the FWHMs of the DCRCs were 127 arc sec for a 7 (im thick layer and 119 arc sec for a 17 (im
thick layer. The etch pit densities of the HgCdTe were 2.3 x 106 cm2 at 7 ^m and 1.5 x 106 cm-2 at 17 um. 相似文献
3.
F. T. Smith P. W. Norton P. Lo Vecchio N. Hartle M. Weiler N. H. Karam S. Sivananthan Y. P. Chen 《Journal of Electronic Materials》1995,24(9):1287-1292
The growth of high quality (111)B oriented HgCdTe layers on CdZnTe/GaAs/Si and CdTe/Si substrates by Te-rich slider liquid
phase epitaxy (LPE) is reported. Although the (111) orientation is susceptible to twinning, a reproducible process yielding
twin-free layers with excellent surface morphology has been developed. The electrical properties and dislocation density in
films grown on these substrates are comparable to those measured in HgCdTe layers grown on bulk CdTe substrates using the
same LPE process. This is surprising in view of the large lattice mismatch that exists in these systems. We will report details
of both the substrate and HgCdTe growth processes that are important to obtaining these results. 相似文献
4.
H. Ebe T. Okamoto H. Nishino T. Saito Y. Nishijima M. Uchikoshi M. Nagashima H. Wada 《Journal of Electronic Materials》1996,25(8):1358-1361
CdTe epilayers were grown directly on (100), (211), and (111) silicon substrates by metalorganic chemical vapor deposition
(MOCVD). The crystallinity and the growth orientation of the CdTe film were dependent on the surface treatment of the Si substrate.
The surface treatment consisted of exposure of the Si surface to diethyltelluride (DETe) at temperatures over 600°C prior
to CdTe growth. Direct growth of CdTe on (100) Si produced polycrystalline films whereas (lll)B single crystals grew when
Si was exposed to DETe prior to CdTe growth. On (211) Si, single crystal films with (133)A orientation was obtained when grown
directly; but produced films with (211)A orientation when the Si surface was exposed to DETe. On the other hand, only (lll)A
CdTe films were possible on (111) Si, both with and without Te source exposure, although twinning was increased after exposure.
The results indicate that the exposure to a Te-source changes the initial growth stage significantly, except for the growth
on (111) Si. We propose a model in which a Te atom replaces a Si atom that is bound to two Si atoms. 相似文献
5.
L. A. Almeida Y. P. Chen J. P. Faurie S. Sivananthan David J. Smith S. -C. Y. Tsen 《Journal of Electronic Materials》1996,25(8):1402-1405
We have systematically studied the growth of CdTe (lll)B on Si(001)with different atomic step structures, defined uniquely
by miscut tilt angle and direction. X-ray double crystal rocking curve (DCRC) analysis has been used to evaluate the crystalline
quality and twin content of the films. High-resolution electron microscopy has been used to examine the CdTe(lll)B/Si(001)
interface and to follow the microstructural evolution as a function of distance from the interface. Our results show that
the formation of double domains and twins is very sensitive to the tilt parameters. When growth conditions are optimized,
twins are not observed at distances greater than about 2.5 microns from the substrate surface. The best quality films exhibit
a DCRC FWHM of 60 arc sec, for a film thickness of 17 μm, the lowest value ever reported for heteroepitaxial growth of CdTe
on Si or GaAs. In efforts to improve the nucleation process, precursors such as Te and As have been used, and we have shown
that they improve the stability of the heterointerface. 相似文献
6.
W. J. Hamilton J. A. Vigil W. H. Konkel V. B. Harper S. M. Johnson 《Journal of Electronic Materials》1993,22(8):879-885
Epitaxial layers of CdTe were grown by metalorganic chemical vapor deposition on surfaces of single crystal, {100} GaAs which
had been ground, polished, and etched to a spherically shaped done. This dome-shaped surface allowed the morphological and
structural properties of the epitaxial CdTe layers to be determined for all 360° of azimuth and up to 15° of polar angle from
the [100] axis within a single growth experiment. At two growth temperatures, approximately 275 and 375°C, the results show
distinct twofold rotational symmetry in both morphology and crystal perfection as determined by x-ray rocking curve measurement.
Surface morphology is superior at azimuths near tilts toward the <111>A pole. Four-sided pyramidal hillocks appear at other
azimuths and at 0° tilt; the symmetry of the hillocks diminishes as the tilt increases. The orientations for growth which
simultaneously minimize the surface defects and rocking curve full-width half-maximum appear to be at locations on the surface
where the surface normal is tilted 3–4° toward the <111>A or <111>B, depending on the temperature regime chosen. Epitaxial
layers grown on planar wafers of {100}GaAs tilted toward <111>Ga and <111>As show surface morphology essentially identical
to the dome at these orientations. The surface morphology of CdTe growth on GaAs/Si wafers suggests that these layers are
tilted toward the <111>B. 相似文献
7.
报道了用MBE的方法,在3英寸Si衬底上制备ZnTe/CdTe(211)B复合衬底材料的初步研究结果,该研究结果将能够直接应用于大面积Si基HgCdTe IRFPA材料的生长.经过Si(211)衬底低温表面处理、ZnTe低温成核、高温退火、高温ZnTe、CdTe层的生长研究,用MBE方法成功地获得了3英寸Si基ZnTe/CdTe(211)B复合衬底材料.CdTe厚度大于10μm,XRD FWHM平均值为120arc sec,最好达到100arc sec,无(133)孪晶和其他多晶晶向. 相似文献
8.
H. Nishino S. Murakami T. Saito Y. Nishijima H. Takigawa 《Journal of Electronic Materials》1995,24(5):533-537
We studied dislocation etch pit density (EPD) profiles in HgCdTe(lOO) layers grown on GaAs(lOO) by metalorganic chemical vapor
deposition. Dislocation profiles in HgCdTe(lll)B and HgCdTe(lOO) layers differ as follows: Misfit dislocations in HgCdTe(lll)B
layers are concentrated near the HgCdTe/CdTe interfaces because of slip planes parallel to the interfaces. Away from the HgCdTe/CdTe
interface, the HgCdTe(111)B dislocation density remains almost constant. In HgCdTe(lOO) layers, however, the dislocations
propagate monotonically to the surface and the dislocation density decreases gradually as dislocations are incorporated with
increasing HgCdTe(lOO) layer thicknesses. The dislocation reduction was small in HgCdTe(lOO) layers more than 10 μm from the
HgCdTe/CdTe interface. The CdTe(lOO) buffer thickness and dislocation density were similarly related. Since dislocations glide
to accommodate the lattice distortion and this movement increases the probability of dislocation incorporation, incorporation
proceeds in limited regions from each interface where the lattice distortion and strain are sufficient. We obtained the minimum
EPD in HgCdTe(100) of 1 to 3 x 106 cm-2 by growing both the epitaxial layers more than 8 μm thick. 相似文献
9.
We discuss various possibilities for determining the orientation of CdTe layers grown on (001) GaAs and in particular, determining
the (001) orientation. This growth orientation is characterized by a three dimensional growth mechanism which controls the
growth in the (111) orientation. We show that a thin layer of ZnTe deposited directly on the oxide free GaAs surface can be
used to determine the (001) orientation, eliminate (111) phases and enhance a two dimensional growth of the CdTe layer, resulting
in an improved crystalline quality and a smooth surface morphology. CdTe layers grown in the (111) direction on oxide free
(001) GaAs substrates contain (111) microtwins and an intermixed (001) phase.
This work is a part of a Ph.D. thesis to be submitted to the Weizmann Institute of Science. 相似文献
10.
K. Shigenaka K. Matsushita L. Sugiura F. Nakata K. Hirahara M. Uchikoshi M. Nagashima H. Wada 《Journal of Electronic Materials》1996,25(8):1347-1352
Orientation dependence of HgCdTe epilayers grown by MOCVD on Si substrates was studied. Substrate orientation is considered
to be one of the most sensitive factors to enable hetero-epitaxial growth on silicon substrates, especially in the case of
a low temperature growth process. The present work was carried out with characterized features of a low temperature process
for HgCdTe growth on Si and using a thin CdTe buffer layer. The (100), (100) misoriented toward [110], (311), (211), (111),
and (331) oriented Si substrates were used in the present work. The best results were obtained on (211)Si substrates with
an x-ray full width at half maximum of 153 arc sec for a 5 (im thickness HgCdTe layer and 69 arc sec for a 10 um thickness
layer. It was found that the effective lattice mismatch of CdTe/Si heterosystem was reduced to 0.6% (for the 611 lattice spacing
of CdTe and 333 spacing of Si) in the case of (133)CdTe/(211)Si. 相似文献
11.
Microstructural and optical characterization of CdTe(211)B/ZnTe/Si(211) grown by molecular beam epitaxy 总被引:2,自引:0,他引:2
S. Rujirawat David J. Smith J. P. Faurie G. Neu V. Nathan S. Sivananthan 《Journal of Electronic Materials》1998,27(9):1047-1052
CdTe layers have been grown by molecular beam epitaxy on 3 inch nominal Si(211) under various conditions to study the effect
of growth parameters on the structural quality. The microstructure of several samples was investigated by high resolution
transmission electron microscopy (HRTEM). The orientation of the CdTe layers was affected strongly by the ZnTe buffer deposition
temperature. Both single domain CdTe(133)B and CdTe(211)B were obtained by selective growth of ZnTe buffer layers at different
temperatures. We demonstrated that thin ZnTe buffer layers (<2 nm) are sufficient to maintain the (211) orientation. CdTe
deposited at ∼300°C grows with its normal lattice parameter from the onset of growth, demonstrating the effective strain accommodation
of the buffer layer. The low tilt angle (<1°) between CdTe[211] and Si[211] indicates that high miscut Si(211) substrates
are unnecessary. From low temperature photoluminescence, it is shown that Cd-substituted Li is the main residual impurity
in the CdTe layer. In addition, deep emission bands are attributed to the presence of AsTe and AgCd acceptors. There is no evidence that copper plays a role in the impurity contamination of the samples. 相似文献
12.
Kwang-Chon Kim Hyun Jae Kim Sang-Hee Suh M. Carmody S. Sivananthan Jin-Sang Kim 《Journal of Electronic Materials》2010,39(7):863-867
Single-crystalline CdTe(133) films have been grown by metalorganic chemical vapor deposition on Si(211) substrates. We studied
the effect of various growth parameters on the surface morphology and structural quality of CdTe films. Proper oxide removal
from the Si substrate is considered to be the principal factor that influences both the morphology and epitaxial quality of
the CdTe films. In order to obtain single-crystalline CdTe(133) films, a two-stage growth method was used, i.e., a low-temperature
buffer layer step and a high- temperature growth step. Even when the low-temperature buffer layer shows polycrystalline structure,
the overgrown layer shows single-crystalline structure. During the subsequent high-temperature growth, two-dimensional crystallites
grow faster than other, randomly distributed crystallites in the buffer layer. This is because the capturing of adatoms by
steps occurs more easily due to increased adatom mobility. From the viewpoint of crystallographic orientation, it is assumed
that the surface structure of Si(211) consists of (111) terrace and (100) step planes with an interplanar angle of 54.8°.
This surface structure may provide many preferable nucleation sites for adatoms compared with nominally flat Si(100) or (111)
surfaces. The surface morphology of the resulting films shows macroscopic rectangular-shaped terrace—step structures that
are considered to be a (111) terrace with two {112} step planes directed toward 〈110〉. 相似文献
13.
14.
The relationship between twin formation and the growth conditions for (111) HgCdTe epitaxial layers grown by metalorganic chemical vapor deposition was investigated. The existence of twins was confirmed by x-ray diffraction and cross-sectional transmission electron microscopy. The x-ray diffraction intensity of the 180°ø rotated 422 asymmetric reflection with that of the 422 asymmetric reflection was compared to detect the presence of twins. The layer obtained using a low growth rate and a low Hg partial pressure showed double-positioning (DP) twins. The twins became lamellar as the growth rate increased. Twin-free HgCdTe epitaxial layers were obtained under a high growth rate and a high Hg partial pressure. These results suggest a model for twin formation based on the difference in the growth mechanism of HgTe and CdTe. Twin-free (111) HgCdTe epitaxial layers were reproducibly obtained without using inclined substrates by optimizing the growth conditions by using this model. 相似文献
15.
W. F. ZHAO R. N. JACOBS M. JAIME-VASQUEZ L. O. BUBULAC DAVID J. SMITH 《Journal of Electronic Materials》2011,40(8):1733-1737
Transmission electron microscopy and small-probe microanalysis have been used to investigate the microstructure and compositional
profiles of CdTe(211)B/ZnTe/Si(211) heterostructures. Thin ZnTe buffer layers and subsequent thick CdTe layers were grown
on Si(211) substrates using molecular beam epitaxy. Many {111}-type stacking faults were found to be present throughout the
entire ZnTe layer, terminating near the point of initiation of CdTe growth. A rotation angle of about 3.5° was observed between
lattice planes of the Si substrate and the final CdTe epilayer. Local lattice parameter measurement and elemental profiles
indicated that some intermixing of Zn and Cd had taken place. The average widths of the ZnTe layer and the (Cd,Zn)Te transition
region were found to be roughly 6.5 nm and 3.5 nm, respectively. 相似文献
16.
Kwang-Chon Kim Seung Hyub Baek Hyun Jae Kim Jin Dong Song Jin-Sang Kim 《Journal of Electronic Materials》2012,41(10):2795-2798
Epitaxial CdTe thin films were grown on GaAs/Si(001) substrates by metalorganic chemical vapor deposition using thin GaAs as a buffer layer. The interfaces were investigated using high-resolution transmission electron microscopy and geometric phase analysis strain mapping. It was observed that dislocation cores exist at the CdTe/GaAs interface with periodic distribution. The spacing of the misfit dislocation was measured to be about 2?nm, corresponding to the calculated spacing of a misfit dislocation (2.6?nm) in CdTe/Si with Burgers vector of a[110]/2. From these results, it is suggested that the GaAs buffer layer effectively absorbs the strain originating from the large lattice mismatch between the CdTe thin film and Si substrate with the formation of periodic structural defects. 相似文献
17.
Heteroepitaxy of HgCdTe(112) infrared detector structures on Si(112) substrates by molecular-beam epitaxy 总被引:4,自引:0,他引:4
T. J. De Lyon R. D. Rajavel J. E. Jensen O. K. Wu S. M. Johnson C. A. Cockrum G. M. Venzor 《Journal of Electronic Materials》1996,25(8):1341-1346
High-quality, single-crystal epitaxial films of CdTe(112)B and HgCdTe(112)B have been grown directly on Si(112) substrates
without the need for GaAs interfacial layers. The CdTe and HgCdTe films have been characterized with optical microscopy, x-ray
diffraction, wet chemical defect etching, and secondary ion mass spectrometry. HgCdTe/Si infrared detectors have also been
fabricated and tested. The CdTe(112)B films are highly specular, twin-free, and have x-ray rocking curves as narrow as 72
arc-sec and near-surface etch pit density (EPD) of 2 × 106 cm−2 for 8 μm thick films. HgCdTe(112)B films deposited on Si substrates have x-ray rocking curve FWHM as low as 76 arc-sec and
EPD of 3-22 × 106 cm−2. These MBE-grown epitaxial structures have been used to fabricate the first high-performance HgCdTe IR detectors grown directly
on Si without use of an intermediate GaAs buffer layer. HgCdTe/Si infrared detectors have been fabricated with 40% quantum
efficiency and R0A = 1.64 × 104 Ωm2 (0 FOV) for devices with 7.8 μm cutoff wavelength at 78Kto demonstrate the capability of MBE for growth of large-area HgCdTe
arrays on Si. 相似文献
18.
本文对Ag纳米线中的五次孪晶结构进行了深入系统的透射电镜研究。首次获得了Ag纳米线截面的五次孪晶结构的高分辨图像和电子衍射花样;研究了单根孪晶Ag纳米线中五次孪晶的结构特性。结果表明:Ag纳米线沿着[110]方向生长,具有显著的五次孪晶结构特点,其中五次孪晶是由五个{111}晶体旋转组成。并针对五重旋转孪晶产生7°20′本征间隙的这一典型结构问题,进行了统计实验分析,提出了纳米线中五次孪晶的新的结构模型。电子能量损失谱(EELS)研究表明:五次孪晶的中心部位相对于Ag单晶,其Ag M4,5峰向低能量方向有轻微漂移。单根纳米线的选区电子衍射或者是由[112]和[110]方向,或者是由[110]和[111]方向叠加产生的。对五次孪晶纳米线高温动态行为的透射电镜原位观察将有利于了解纳米线的生长机理。 相似文献
19.
A. Krost F. Heinrichsdorff F. Schnabel K. Schatke D. Bimberg H. Cerva 《Journal of Electronic Materials》1994,23(2):135-139
The growth of InP by low-pressure metalorganic chemical vapor deposition on vicinal Si(111), misoriented 3° toward [1-10],
is reported. Antiphase domain-free InP is obtained without any preannealing of the Si substrate. Crystallographic, optical,
and electrical properties of the layers are significantly improved as compared to the best reported InP grown on Si(001).
The high structural perfection is demonstrated by a full width at half maximum (FWHM) of 121 arcs for the (111) Bragg reflex
of InP (thickness = 3.4 μm) as obtained by double crystal x-ray diffraction. The low-temperature photoluminescence (PL) efficiency
is 70% of that of homoepitaxially grown InP layers. The FWHM of the near-gap PL peak is only 2.7 meV as compared to 4.5 meV
of the best material grown on Si(001). For the first time, InP:Fe layers with semi-insulating characteristics (ρ > 3 × 107 Ω-cm) have been grown by compensating the low residual background doping using ferrocene. Semi-insulating layers are prerequisite
for any device application at ultrahigh frequencies. 相似文献
20.
S. S. You B. Rodricks S. Sivananthan J. P. Faurie P. A. Montano 《Journal of Electronic Materials》1996,25(8):1306-1311
We have been fabricating x-ray photoconductor linear array detectors using molecular beam epitaxially (MBE) grown (lll)B undoped
CdTe layers on (100) Si substrates. A novel technique was developed to remove the Si and to mount the fragile MBE grown CdTe
layers onto insulating ceramic substrates. 256 channel linear photoconductor array devices were fabricated on the resulting
CdTe layers. The resistivity of MBE (lll)B CdTe was high (>108 \cm) enough to utilize the material for low energy (8 ~ 25
keV) x-ray detectors. The stability of the detectors are satisfactory, and they were tested at room temperature routinely
for over a year. The performance of the photoconductor was greatly improved when the detector was cooled to 230K. Due to its
reduced dark current at low temperatures, the dynamic range of the detector response increased to nearly four decades at 230K. 相似文献